Turbocharger turbine wastegate assembly

ABSTRACT

A turbocharger turbine wastegate assembly includes a turbine housing that includes a wastegate seat and a bore; a bushing with a stepped bore that includes an axial face; a wastegate that includes a shaft, a plug and an arm, where the shaft includes an end portion, a first axial face, a journal portion, a second axial face and a shoulder portion, where the first axial face is defined at least in part by an end portion diameter and a journal portion diameter, and where the second axial face is defined at least in part by the journal portion diameter and a shoulder portion diameter; a mesh spacer disposed radially about an axial length of the end portion of the shaft between the axial face of the stepped bore of the bushing and the first axial face of the shaft; and a control arm connected to the end portion of the shaft where an axial length of the bushing is disposed between the mesh spacer and the control arm.

RELATED APPLICATIONS

This application is a continuation-in-part of a co-pending US patentapplication having Ser. No. 15/218,045, filed 24 Jul. 2016, which isincorporated by reference herein, and this application is acontinuation-in-part of a co-pending US patent application having Ser.No. 15/218,048, filed 24 Jul. 2016, which is incorporated by referenceherein.

TECHNICAL FIELD

Subject matter disclosed herein relates generally to turbomachinery forinternal combustion engines and, in particular, to turbocharger turbinewastegate assemblies.

BACKGROUND

A turbocharger turbine wastegate is typically a valve that can becontrolled to selectively allow at least some exhaust to bypass aturbine. Such a valve may be part of an assembly such as a turbochargerturbine wastegate assembly, which can be part of a turbocharger. Wherean exhaust turbine drives a compressor for boosting inlet pressure to aninternal combustion engine (e.g., as in a turbocharger), a wastegateprovides a means to control the boost pressure.

A so-called internal wastegate is integrated at least partially into aturbine housing. An internal wastegate typically includes a flappervalve (e.g., a plug), a crank arm, a shaft or rod, and an actuator. Aplug of a wastegate often includes a flat disk shaped surface that seatsagainst a flat seat (e.g., a valve seat or wastegate seat) disposedabout an exhaust bypass opening, though various plugs may include aprotruding portion that extends into an exhaust bypass opening (e.g.,past a plane of a wastegate seat).

In a closed position, a wastegate plug should be seated against awastegate seat (e.g., seating surface) with sufficient force toeffectively seal an exhaust bypass opening (e.g., to prevent leaking ofexhaust from a high pressure exhaust supply to a lower pressure region).Often, an internal wastegate is configured to transmit force from an armto a plug (e.g., as two separate, yet connected components). Duringengine operation, load requirements for a wastegate vary with pressuredifferential. High load requirements can generate high mechanicalstresses in a wastegate's kinematics components, a fact which has led insome instances to significantly oversized component design to meetreliability levels (e.g., as demanded by engine manufacturers).Reliability of wastegate components for gasoline engine applications isparticularly important where operational temperatures and exhaustpulsation levels can be quite high.

Various examples of wastegates, wastegate components and wastegaterelated processes are described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the various methods, devices,assemblies, systems, arrangements, etc., described herein, andequivalents thereof, may be had by reference to the following detaileddescription when taken in conjunction with examples shown in theaccompanying drawings where:

FIG. 1 is a diagram of a turbocharger and an internal combustion enginealong with a controller and an example of a vehicle;

FIG. 2 is a series of view of an example of an assembly that includes awastegate;

FIG. 3 is a series of views of an example of an assembly that includes awastegate and views of an example of a wastegate;

FIG. 4 is a perspective view of an example of a turbocharger;

FIG. 5 is an example of a plot of data;

FIG. 6 is a cut-away view of an example of an assembly;

FIG. 7 is a series of views of examples of mesh spacers;

FIG. 8 is a cross-sectional view of an example of a bushing;

FIG. 9 is a series of views of an example of a mesh spacer in differentstates;

FIG. 10 is a plan view and a cut-away view of an example of a wastegateand an example of a mesh spacer as part of an example assembly;

FIG. 11 is a cut-away view of an example of a housing and an example ofa bushing as part of an example assembly;

FIG. 12 is a cut-away view of an example of an assembly;

FIG. 13 is a cut-away view of an example of an assembly; and

FIG. 14 is a cut-away view of an example of an assembly.

DETAILED DESCRIPTION

Turbochargers are frequently utilized to increase output of an internalcombustion engine. Referring to FIG. 1, as an example, a system 100 caninclude an internal combustion engine 110 and a turbocharger 120. Asshown in FIG. 1, the system 100 may be part of a vehicle 101 where thesystem 100 is disposed in an engine compartment and connected to anexhaust conduit 103 that directs exhaust to an exhaust outlet 109, forexample, located behind a passenger compartment 105. In the example ofFIG. 1, a treatment unit 107 may be provided to treat exhaust (e.g., toreduce emissions via catalytic conversion of molecules, etc.).

As shown in FIG. 1, the internal combustion engine 110 includes anengine block 118 housing one or more combustion chambers thatoperatively drive a shaft 112 (e.g., via pistons) as well as an intakeport 114 that provides a flow path for air to the engine block 118 andan exhaust port 116 that provides a flow path for exhaust from theengine block 118.

The turbocharger 120 can act to extract energy from the exhaust and toprovide energy to intake air, which may be combined with fuel to formcombustion gas. As shown in FIG. 1, the turbocharger 120 includes an airinlet 134, a shaft 122, a compressor housing assembly 124 for acompressor wheel 125, a turbine housing assembly 126 for a turbine wheel127, another housing assembly 128 and an exhaust outlet 136. The housing128 may be referred to as a center housing assembly as it is disposedbetween the compressor housing assembly 124 and the turbine housingassembly 126. The shaft 122 may be a shaft assembly that includes avariety of components. The shaft 122 may be rotatably supported by abearing system (e.g., journal bearing(s), rolling element bearing(s),etc.) disposed in the housing assembly 128 (e.g., in a bore defined byone or more bore walls) such that rotation of the turbine wheel 127causes rotation of the compressor wheel 125 (e.g., as rotatably coupledby the shaft 122). As an example a center housing rotating assembly(CHRA) can include the compressor wheel 125, the turbine wheel 127, theshaft 122, the housing assembly 128 and various other components (e.g.,a compressor side plate disposed at an axial location between thecompressor wheel 125 and the housing assembly 128).

In the example of FIG. 1, a variable geometry assembly 129 is shown asbeing, in part, disposed between the housing assembly 128 and thehousing assembly 126. Such a variable geometry assembly may includevanes or other components to vary geometry of passages that lead to aturbine wheel space in the turbine housing assembly 126. As an example,a variable geometry compressor assembly may be provided.

In the example of FIG. 1, a wastegate valve (or simply wastegate) 135 ispositioned proximate to an exhaust inlet of the turbine housing assembly126. The wastegate valve 135 can be controlled to allow at least someexhaust from the exhaust port 116 to bypass the turbine wheel 127.Various wastegates, wastegate components, etc., may be applied to aconventional fixed nozzle turbine, a fixed-vaned nozzle turbine, avariable nozzle turbine, a twin scroll turbocharger, etc.

In the example of FIG. 1, an exhaust gas recirculation (EGR) conduit 115is also shown, which may be provided, optionally with one or more valves117, for example, to allow exhaust to flow to a position upstream thecompressor wheel 125.

FIG. 1 also shows an example arrangement 150 for flow of exhaust to anexhaust turbine housing assembly 152 and another example arrangement 170for flow of exhaust to an exhaust turbine housing assembly 172. In thearrangement 150, a cylinder head 154 includes passages 156 within todirect exhaust from cylinders to the turbine housing assembly 152 whilein the arrangement 170, a manifold 176 provides for mounting of theturbine housing assembly 172, for example, without any separate,intermediate length of exhaust piping. In the example arrangements 150and 170, the turbine housing assemblies 152 and 172 may be configuredfor use with a wastegate, variable geometry assembly, etc.

In FIG. 1, an example of a controller 190 is shown as including one ormore processors 192, memory 194 and one or more interfaces 196. Such acontroller may include circuitry such as circuitry of an engine controlunit (ECU). As described herein, various methods or techniques mayoptionally be implemented in conjunction with a controller, for example,through control logic. Control logic may depend on one or more engineoperating conditions (e.g., turbo rpm, engine rpm, temperature, load,lubricant, cooling, etc.). For example, sensors may transmit informationto the controller 190 via the one or more interfaces 196. Control logicmay rely on such information and, in turn, the controller 190 may outputcontrol signals to control engine operation. The controller 190 may beconfigured to control lubricant flow, temperature, a variable geometryassembly (e.g., variable geometry compressor or turbine), a wastegate(e.g., via an actuator), an electric motor, or one or more othercomponents associated with an engine, a turbocharger (or turbochargers),etc. As an example, the turbocharger 120 may include one or moreactuators and/or one or more sensors 198 that may be, for example,coupled to an interface or interfaces 196 of the controller 190. As anexample, the wastegate 135 may be controlled by a controller thatincludes an actuator responsive to an electrical signal, a pressuresignal, etc. As an example, an actuator for a wastegate may be amechanical actuator, for example, that may operate without a need forelectrical power (e.g., consider a mechanical actuator configured torespond to a pressure signal supplied via a conduit).

FIG. 2 shows an example of an assembly 200 that includes a turbinehousing 210 that includes a flange 211, a bore 212, an inlet conduit213, a turbine wheel opening 214, a spiral wall 215, an exhaust outletopening 216, a shroud wall 220, a nozzle 221, a volute 222 formed inpart by the spiral wall 215, a wastegate wall 223 that extends to awastegate seat 226, and an exhaust chamber 230. In the example of FIG.2, the turbine housing 210 may be a single piece or multi-piece housing.As an example, the turbine housing 210 may be a cast component (e.g.,formed via a sand casting or another casting process). The turbinehousing 210 includes various walls, which can define features such asthe bore 212, the turbine wheel opening 214, the exhaust outlet opening216, the chamber 230, etc. In particular, the wastegate wall 223 definesa wastegate passage in fluid communication with the inlet conduit 213where a wastegate control linkage 240 and a wastegate arm and plug 250are configured for opening and closing the wastegate passage (e.g., forwastegating exhaust).

In the example of FIG. 2, the wastegate control linkage 240 includes abushing 242 configured for receipt by the bore 212 of the turbinehousing 210, a control arm 244 and a peg 246 and the wastegate arm andplug 250 includes a shaft 252, a shaft end 253, an arm 254 and a plug256. As shown, the bushing 242 is disposed between the bore 212 and theshaft 252, for example, to support rotation of the shaft 252, to sealthe chamber 230 from an exterior space, etc. The bore 212, the bushing242 and the shaft 252 may each be defined by a diameter or diameters aswell as one or more lengths. For example, the shaft 252 includes adiameter D_(s), the bore 212 includes a diameter D_(B) while the bushing242 includes an inner diameter D_(bi) and an outer diameter D_(bo). Inthe example of FIG. 2, when the various components are assembled, thediameters may be as follows: D_(B)>D_(bo)>D_(bi)>D_(s). As to lengths, alength of the shaft 252 exceeds a length of the bushing 242, whichexceeds a length of the bore 212. Such lengths may be defined withrespect to a shaft axis z_(s), a bushing axis z_(b) and a bore axisz_(B). As shown, the bushing 242 is disposed axially between a shoulderof the shaft 252 and the control arm 244 of the control linkage 240.

In the example of FIG. 2, a gap Δz is shown between a surface of thebushing 242 and a surface of the control arm 244, which allows for axialmovement of the shaft 252, for example, to facilitate self-centering ofthe plug 256 with respect to the wastegate seat 226.

As an example, the assembly 200 may be fitted to an exhaust conduit orother component of an internal combustion engine (see, e.g., examples ofFIG. 1) via the flange 211 such that exhaust is received via the inletconduit 213, directed to the volute 222. From the volute 222, exhaust isdirected via the nozzle 221 to a turbine wheel disposed in the turbinehousing 210 via the opening 214 to flow and expand in a turbine wheelspace defined in part by the shroud wall 220. Exhaust can then exit theturbine wheel space by flowing to the chamber 230 and then out of theturbine housing 210 via the exhaust outlet opening 216.

As to wastegating, upon actuation of the control linkage 240 (e.g., byan actuator coupled to the peg 246), the wastegate arm and plug 250 maybe rotated such that at least a portion of the received exhaust can flowin the wastegate passage defined by the wastegate wall 223, past thewastegate seat 226 and into the chamber 230, rather than through thenozzle 221 to the turbine wheel space. The wastegated portion of theexhaust may then exit the turbine housing 210 via the exhaust outletopening 216 (e.g., and pass to an exhaust system of a vehicle, berecirculated in part, etc.).

As an example, the control linkage 240 may exert a force that acts toforce the plug 256 in a direction toward the wastegate seat 226. Forexample, an actuator may include a biasing mechanism (e.g., a spring,etc.) that exerts force, which may be controllably overcome, at least inpart, for rotating the plug 256 away from the wastegate seat 226 (e.g.,for wastegating). As an example, an actuator may be mounted to aturbocharger (e.g., mounted to a compressor assembly, etc.). As anexample, an actuator may be a linear actuator, for example, thatincludes a rod that moves along an axis. Depending on orientation of aplug, a shaft, a control linkage and such a rod, to maintain the plug ina closed position, the rod may exert a downward force (e.g., away fromthe control linkage as in the example of FIG. 2) or the rod may exert anupward force (e.g., toward the control linkage). For example, where thecontrol arm 244 (e.g., and the peg 246) of the control linkage 240 areoriented on the same “side” as the plug 256 with respect to the shaft252, a downward force applied to the control arm 244 (e.g., via the peg246) may act to maintain the plug 256 in a closed position with respectto the wastegate seat 226; whereas, where, for example, an approximately180 degree span exists between a plug and a control arm, an upward forceapplied to the control arm may act to maintain the plug in a closedposition with respect to a wastegate seat.

As an example, a rod of an actuator may be biased to exert a force on acontrol linkage that causes the control linkage to exert a force on aplug (see, e.g., the plug 256) such that the plug seats against awastegate seat (see, e.g., the wastegate seat 226). In such an example,the actuator may at least in part overcome the force that biases the rodsuch that a shaft rotates the plug away from the wastegate seat. Forexample, in FIG. 2, to initiate wastegating, the entire plug 256 rotatesabout an axis of the shaft 252 and moves away from the wastegate seat226 (e.g., without any portion of the plug 256 moving into a wastegateopening defined by the wastegate seat 226). As an example, the movingaway of the plug 256 may be facilitated by exhaust pressure. Forexample, in a closed position, the plug 256 experiences a pressuredifferential where pressure is higher below the plug 256 and less abovethe plug 256. In such an example, the pressure below the plug 256 actsin a direction that is countered by the closing force applied to theplug 256 via the control linkage 240 (e.g., the pressure differentialacts to bias the plug 256 toward an open position). Accordingly, theclosing force applied to the plug 256 should overcome pressure forcefrom below the plug 256. Further, where the shaft 252 may include someplay (see, e.g., Δz, etc.), the closing force applied to the plug 256may cause the plug 256 to self-center with respect to the wastegate seat226 (e.g., to facilitate sealing, to avoid exhaust leakage, etc.).

In the example of FIG. 2, the axes of the bore 212, the bushing 242 andthe shaft 252 are shown as being aligned (e.g., defining a common axis),however, during assembly, operation, etc., some misalignment may occur.For example, over time, clearances between the various components (e.g.,plug, arm, shaft, bore, bushing, etc.) can change. Forces that can causesuch change include aerodynamic excitation, high temperatures,temperature cycling (e.g., temperatures <−20 degrees C. to >1000 degreesC.), chemical attack, friction, deterioration of materials, etc. For atleast the foregoing reasons, it can be difficult to maintain effectivesealing of a wastegate opening over the lifetime of an exhaust turbineassembly. As to temperature, problems at high temperatures generallyinclude wear and loss of function and consequently leakage, lack ofcontrollability or a combination of leakage and uncontrollability.

As an example, a plug may include a contact portion and an aerodynamicportion. For example, a plug may include a radiused portion as a contactportion that contacts a surface of a wastegate seat in a closed stateand an aerodynamic portion that defines a flow passage with respect tothe surface of the wastegate seat in an open state. In such an example,the aerodynamic portion may extend into a wastegate passage in theclosed state (e.g., without contacting a surface that defines thewastegate passage, a surface of the wastegate seat, etc.). As anexample, in an assembly, such a plug may be configured to self-centerwith respect to a wastegate seat (e.g., in a closed state). As anexample, a surface of a wastegate seat may be conical, which mayfacilitate self-centering of a contact portion of a plug. As an example,one or more clearances may exist in an assembly for a wastegate shaftwith respect to a bushing such that the wastegate shaft may move in amanner that allows for self-centering of a wastegate plug, operativelycoupled to the wastegate shaft, with respect to a wastegate seat.

FIG. 3 shows a view of a portion of the assembly 200 of FIG. 2 alongwith views of an example of the wastegate arm and plug 250. As describedabove, the wastegate arm and plug 250 can include a shaft 252, a shaftend 253, an arm 254 and a plug 256. As an example, the wastegate arm andplug 250 can be a monoblock wastegate arm and plug where monoblockrefers to a component being made of a single unitary “block” (e.g., viamachining of metallic stock or other process) or formed as a singleunitary component (e.g., via casting or other process), which may be ina final or near final form. As an example, a shaft may be a componentthat is formed separately and fit to a monoblock component that includesan arm and a plug. In such an example, the shaft may be fit in a mannerthat physically prevents movement of the shaft separately from movementof the arm and the plug. As an example, a monoblock arm and plug and/ora monoblock shaft, arm and plug may be made of a material such as HK 30alloy (e.g., C at 0.20-0.50; Cr at 24.0-27.0; Ni at 19.0-22.0; Si at0.75-1.30; Mn at 1.50; Mo at 0.20-0.30; Fe at balance; and otheroptionally Nb at 1.00-1.75, noting values as weight percent).

In the example of FIG. 3, the wastegate arm and plug 250 includes ashoulder 255. Such a shoulder may define an axial face, which may be anannular axial face. As an example, the shoulder 255 may abut an end ofthe bushing 242. As an example, the shaft 252 may be considered to be ofa length defined from the end of the shaft 253 to the shoulder 255 ormay be considered to be of a length defined from the end of the shaft253 to, for example, a centerline of the arm 254. As shown in FIG. 3, adimension ΔSP can be a shaft-to-plug dimension where rotation of theshaft 252 about its longitudinal axis causes rotation of the plug 256along an arc defined by a radius, which can be the dimension ΔSP.

As implemented in an internal combustion engine application, somemisalignment of components of a wastegate assembly may occur. In FIG. 3,the shaft 252 is shown as including an axis z, that may becomemisaligned with an axis z_(b) of the bushing 242. For example, thebushing 242 may be received with minimal radial clearance with respectto the bore 212 of the housing 210 while a radial clearance may exist(e.g., a larger radial clearance) between the shaft 252 and an innersurface of the bushing 242. In such a manner, the shaft 252 may tiltwith respect to the axis of the bushing 242 and, for example, the axisof the bore 212 (z_(B)). As an example, contact points may determine amaximal extent of misalignment with respect to tilting of the axis ofthe shaft 252 (z_(s)) with respect to the axis of the bushing 242(z_(b)). As an example, such tilt may be represented by a tilt angle Δφ.

As an example, an axial gap Δz can exist between an outwardly facing endof the bushing 242 disposed at an axial position and an inwardly facingsurface of the control arm 244 disposed at an axial position. In such anexample, the axial gap may be defined by the difference between thesetwo axial positions. As an example, the shaft 252 may be able to moveaxially where the axial distance may be limited in part by the end ofthe bushing 242, which defines, in part, the axial gap Δz. For example,the inwardly facing surface of the control arm 244 may contact the endof the bushing 242, which, in turn, may limit axial inward movement ofthe shaft 252.

As mentioned, the shaft 252 may tilt and may move axially where suchmovements may be limited (e.g., via Δz and Δφ). As an example, thewastegate arm and plug 250 may act to self-center with respect to thewastegate seat 226 responsive to force applied to the control arm 244(e.g., which is transmitted to the wastegate arm and plug 250 via theshaft 252, whether integral therewith or operatively coupled thereto).In such an example, self-centering may occur for effective sealing ofthe wastegate within the range of clearances that allow for axial and/orangular movement of the shaft 252.

As an example, during operational use, one or more clearances betweenvarious components (e.g., plug, arm, shaft, bore, bushing, etc.) maychange. Forces that can cause such change include aerodynamicexcitation, high temperatures, temperature cycling (e.g., temperatures<−20 degrees C. to >1000 degrees C.), chemical attack, friction,deterioration of materials, etc. For at least the foregoing reasons, itmay be difficult to maintain effective sealing of a wastegate openingover the lifetime of an exhaust turbine assembly. As to temperature,problems at high temperatures generally include wear and loss offunction and consequently leakage, lack of controllability or acombination of leakage and uncontrollability.

As an example, one or more pieces may be from a blank (e.g., a blankbar, stock, etc.). As an example, one or more pieces may be cast (e.g.,from a molten material that can harden upon cooling). As an example, amaterial of construction of a piece may be a metal. As an example, amaterial of construction of a piece may be an alloy. As an example, amaterial (e.g., a metal, an alloy, etc.) may be selected based onoperational conditions (e.g., operational conditions of an exhaust gasturbine) and, for example, ability to be welded to another piece. As anexample, a unit may be formed of a high temperature metal and/or a hightemperature alloy. As an example, a piece may be formed of an alloy suchas, for example, a NiCrFe-based alloy (e.g., HASTALLOY™ material,INCONEL™ material, etc.) or another alloy. As an example, a piece may beformed of a stainless steel or another type of steel.

As an example, a weld may be formed between two or more components wherethe weld can withstand operating conditions (e.g., temperatures, etc.)of an exhaust gas turbine of a turbocharger operatively coupled to aninternal combustion engine (e.g., gasoline, diesel, flex-fuel, bi-fuel,etc.).

As an example, a plug can include a shape such as, for example, a shapeof a hemisphere (e.g., a substantially hemispherical shell plug, asubstantially hemispherically solid plug, etc.). As an example, a plugcan include a toroidal portion that defines a convex surface that cancontact a wastegate seat. In such an example, the plug can include aprotruding portion that may extend into a portion of a wastegate passageat least in part when the plug is in a closed orientation with respectto the wastegate passage, for example, where the convex surface contactsthe wastegate seat. As an example, a plug can include a concave surface,which may be, for example, a domed concave surface that faces awastegate passage. As an example, a concave surface may be interior to aconvex surface that can contact a wastegate seat. As an example, aconcave surface may act to distribute pressure. As an example, a convexsurface that can extend into a wastegate passage may act to distributepressure in a different manner. For example, where exhaust flows andimpinges upon the convex surface, one or more stagnation points may formthat may also coincide with pressure or force points where pressure orforce may be at a global maximum or local maxima on a plug with respectto exhaust flow.

FIG. 4 shows an example of an assembly 400 that includes an actuator401, an actuation rod 402, an actuator linkage 403, a center housing 407(e.g., to house a bearing, bearings, etc. for a turbocharger shaft,etc.), a compressor housing 409, a turbine housing 410 that includes abore 412, a spiral wall 415 (e.g., that defines, in part, a volute), anexhaust outlet opening 416, a wastegate wall 423 that extends to awastegate seat 426, and an exhaust chamber 430.

In the example of FIG. 4, the turbine housing 410 may be a single pieceor multi-piece housing. As an example, the turbine housing 410 may be acast component (e.g., formed via sand casting or other casting process).As shown, the turbine housing 410 includes various walls, which candefine features such as the bore 412, a turbine wheel opening, anexhaust outlet opening, the chamber 430, etc. In particular, thewastegate wall 423 defines a wastegate passage in fluid communicationwith an inlet conduit where a wastegate control linkage 440 and awastegate shaft, arm and plug unit 450 are configured for opening andclosing the wastegate passage (e.g., for wastegating exhaust).

In the example of FIG. 4, the wastegate control linkage 440 includes abushing 442 configured for receipt by the bore 412 of the turbinehousing 410, a control arm 444 and a peg 446 and the wastegate shaft,arm and plug unit 450 includes a shaft 452, a shaft end 453, an arm 454and a plug 456. As shown, the bushing 442 is disposed between the bore412 and the shaft 452, for example, to support rotation of the shaft452, to seal the chamber 430 from an exterior space, etc. The bore 412,the bushing 442 and the shaft 452 may each be defined by a diameter ordiameters as well as one or more lengths.

As an example, the assembly 400 may be fitted to an exhaust conduit orother component of an internal combustion engine (see, e.g., examples ofFIG. 1) via a flange such that exhaust is received via an inlet conduitthat may direct exhaust to a volute (e.g., or volutes) that may bedefined at least in part by the spiral wall 415. As an example, a volute(e.g., or volutes) may direct exhaust (e.g., via a nozzle or nozzles) toa turbine wheel disposed in the turbine housing 410 where the exhaustmay flow and expand in a turbine wheel space defined in part by theturbine housing 410. Exhaust may then exit the turbine wheel space byflowing to the chamber 430 and then out of the turbine housing 410 viathe exhaust outlet opening 416.

As to wastegating, upon actuation of the control linkage 440 (e.g., bythe actuator linkage 403 being operatively coupled to the peg 446), thewastegate shaft, arm and plug unit 450 may be rotated such that at leasta portion of the received exhaust can flow in the wastegate passagedefined by the wastegate wall 423, past the wastegate seat 426 and intothe chamber 430, rather than through a nozzle to a turbine wheel space.The wastegated portion of the exhaust may then exit the turbine housing410 via the exhaust outlet opening 416 (e.g., and pass to an exhaustsystem of a vehicle, be recirculated in part, etc.).

As an example, the control linkage 440 may exert a force that acts toforce the plug 456 in a direction toward the wastegate seat 426. Forexample, the actuator 401 may include a biasing mechanism (e.g., aspring, etc.) that exerts force, which may be controllably overcome, atleast in part, for rotating the plug 456 away from the wastegate seat426 (e.g., for wastegating). As an example, the actuator 401 may bemounted to the assembly 400. As an example, the actuator 401 may be alinear actuator, for example, for moving the rod 402 along an axis.Depending on orientation of a plug, a shaft, a control linkage and sucha rod, to maintain the plug in a closed position, the rod may exert adownward force (e.g., away from the control linkage as in the example ofFIG. 4) or the rod may exert an upward force (e.g., toward the controllinkage). For example, where the control arm 444 (e.g., and the peg 446)of the control linkage 440 are oriented on the same “side” as the plug456 with respect to the shaft 452, a downward force applied to thecontrol arm 444 (e.g., via the peg 446) may act to maintain the plug 456in a closed position with respect to the wastegate seat 426; whereas,where, for example, an approximately 180 degree span exists between aplug and a control arm, an upward force applied to the control arm mayact to maintain the plug in a closed position with respect to awastegate seat.

As an example, the rod 402 of the actuator 401 may be biased to exert aforce on the control linkage 440 that causes the control linkage 440 toexert a force on the plug 456 such that the plug 456 seats against thewastegate seat 426. In such an example, the actuator 401 may at least inpart overcome the force that biases the rod 402 such that the shaft 452rotates the plug 456 away from the wastegate seat. For example, in FIG.4, to initiate wastegating, the entire plug 456 rotates about an axis ofthe shaft 452 and moves away from the wastegate seat 426 (e.g., withoutany portion of the plug 456 moving into a wastegate opening defined bythe wastegate seat 426). As an example, the moving away of the plug 456may be facilitated by exhaust pressure. For example, in a closedposition, the plug 456 experiences a pressure differential wherepressure is higher below the plug 456 and less above the plug 456. Insuch an example, the pressure below the plug 456 acts in a directionthat is countered by the closing force applied to the plug 456 via thecontrol linkage 440 (e.g., the pressure differential acts to bias theplug 456 toward an open position). Accordingly, the closing forceapplied to the plug 456 should overcome pressure force from below theplug 456. Further, where the shaft 452 may include some play (e.g.,axial play, etc.), the closing force applied to the plug 456 may causethe plug 456 to move with respect to the wastegate seat 426.

As an example, a method can include in situ welding of a wastegate thatincludes a shaft, an arm and a plug. In such an example, the wastegatecan be a monoblock wastegate where at least the arm and plug are aunitary piece. In such an example, the monoblock wastegate can be asingle component that includes a shaft, an arm and a plug, which may bedefined by dimensions. Such dimensions may limit orientation of themonoblock wastegate with respect to a turbine housing that includes abore that can receive the shaft and that includes a wastegate seat thatcan seat the plug to cover a wastegate passage.

As an example, a monoblock wastegate arm and plug can provide variousbenefits when compared to a three piece arm and plug design in terms ofdurability and impact on noise generated by system kinematics.

As mentioned, a plug can include a convex surface that may be, forexample, a portion of a sphere or a portion of a torus. Such a convexsurface may be considered to be a contact surface or a sealing surfacethat can contact a wastegate seat in a closed orientation to obstruct awastegate passage. As an example, a wastegate seat may be defined atleast in part by a portion of a cone. For example, a wastegate seat canbe a conical wastegate seat. In such an example, a convex surface of aplug may self-center with respect to the wastegate seat, for example,due in part to force applied to the plug via a shaft and an arm.

As an example, a method can include in situ connecting of components,for example, via welding. In such an example, the method can includeapplying force to a plug to seat it with respect to a wastegate seat.For example, a tool (e.g., a rod, a jig, etc.) may be used to applyforce to a plug to seat it with respect to a wastegate seat. Such anapproach may act to apply force to substantially center a plug withrespect to a wastegate seat where, for example, welding may be performedto connect components while the plug is substantially centered. As anexample, application of force may act to reduce axial play of anassembly.

FIG. 5 shows an example plot 500 of torque generated by an internalcombustion engine versus time with respect to two different wastegateassemblies 510 and 520. As shown, the wastegate assembly 520 can operatein a manner that decreases time for an internal combustion engine toachieve a level of torque (e.g., a torque target, T_(Target)) whencompared to the wastegate assembly 510, which exhibits some leakage. Asto the lesser time, the wastegate assembly 520 is assembled using ashimming approach. Such an approach allows for achieving a desired levelof torque in a lesser time than the assembly 510 where the desired levelof torque is achieved within a target time (see, e.g., t_(Target)) dueto adequate sealing of a wastegate passage (e.g., a plug portion seatedagainst a wastegate seat to close a wastegate passage). In the exampleplot 500, the profiles of torque versus time correspond to a change ofin operational conditions associated with an amount of exhaust pressure.The example plot 500 demonstrates how a method of manufacture canachieve desired clearances of an assembly that includes a monoblock armand plug such that a desired amount of sealing is exhibited in operationof a turbocharged internal combustion engine. Such an assembly may beless prone to wear, rattling (e.g., noise), performance degradation overtime when compared to an assembly that includes an arm and a plug asseparate pieces. As an example, a monoblock arm and plug approach caninclude a torus as part of a plug and a cone as part of a wastegateseat, for example, in contrast to a flat surface plug and a flat surfacewastegate seat.

FIG. 6 is a cut-away view of an example of an assembly 600 that includesa wastegate 605, a turbine housing 610, a control arm 640, a bushing660, and a mesh spacer 670. Such an assembly can be a turbochargerturbine wastegate assembly, which can be part of a turbocharger turbinehousing assembly. For example, the turbine housing 610 can includevarious features such that it carries, accommodates, etc., the wastegate605 and associated components. As an example, a turbocharger turbinewastegate assembly can be an assembly that attaches to one or morehousing of a turbocharger.

As shown in FIG. 6, the wastegate 605 includes a shaft 650, an arm 680and a plug 690 where the shaft 650 includes an end 652, an end portion653, a journal portion 654, and a shoulder portion 659 where a firstaxial face 655 is defined at least in part by an end portion diameter(d_(e)) and a journal portion diameter (d_(j)) and where a second axialface 657 is defined at least in part by the journal portion diameter anda shoulder portion diameter (d_(ss)). As shown, the journal portion 654can include one or more journal surfaces 655 and 657.

As shown in FIG. 6, the turbine housing 610 includes a bore 612, anexterior surface 617 and an interior surface 619 where the bore 612extends between the exterior surface 617 and the interior surface 619.The turbine housing 610 also includes a wastegate seat 626 that isdefined along the interior surface 619. In the example of FIG. 6, theplug 690 is seated in the wastegate seat 626 (e.g., a surface of theplug 690 contacts a surface of the wastegate seat 626).

As shown in FIG. 6, the control arm 640 includes opposing surfaces 642and 644 and a bore 643 that extends between the opposing surfaces 642and 644. In the example of FIG. 6, a weld 645 fixes the control arm 640to the end portion 653 of the shaft 650 of the wastegate 605. In such anarrangement, at least a portion of the end portion 653 is received bythe bore 643 of the control arm 640; noting that one or more otherarrangements may be utilized to fix the control arm 640 to the shaft 650of the wastegate 605.

As shown in FIG. 6, the bushing 660 includes a stepped bore 661 thatextends between opposing ends 662 and 664, which can be axial faces. Forexample, the end 662 can be an axial face about a smaller diameterportion of the stepped bore 661 and the end 664 can be an axial faceabout a larger diameter portion of the stepped bore 661. As shown inFIG. 6, an axial face 667 is located between the ends 662 and 664 andwithin the stepped bore 661. The axial face 667 can be a shoulder suchas a shoulder of a counter-bore that is formed between the two portionsof the stepped bore 661.

As shown in the example of FIG. 6, the assembly 600 includes: theturbine housing 610 that includes the exterior surface 617, the interiorsurface 619 that includes the wastegate seat 626, and the bore 612 thatextends between the exterior surface 617 and the interior surface 619;the bushing 660 disposed at least partially in the bore 612 of theturbine housing 610 where the bushing 660 includes the stepped bore 661that includes the axial face 667; the wastegate 605 that includes theshaft 650, the arm 680 and the plug 690, where the arm 680 extends fromthe shaft 650 and the plug 690 extends from the arm 680, where the shaft650 includes the end portion 653, the first axial face 655, the journalportion 654, the second axial face 657 and the shoulder portion 659,where the first axial face 655 is defined at least in part by the endportion diameter (d_(e)) and the journal portion diameter (d_(j)), andwhere the second axial face 657 is defined at least in part by thejournal portion diameter (d_(j)) and the shoulder portion diameter(d_(ss)); the mesh spacer 670 disposed radially about an axial length ofthe end portion 653 of the shaft 650 between the axial face 667 of thestepped bore 661 of the bushing 660 and the first axial face 655 of theshaft 650; and the control arm 640 connected to the end portion 653 ofthe shaft 650 where an axial length of the bushing 660 is disposedbetween the mesh spacer 670 and the control arm 640.

In the example of FIG. 6, the shaft 650 can be defined by an axiallength (z_(s)), for example, as measured from the end 652 to a surfaceof the shoulder portion 659 where the shaft 650 transitions to the arm680. Another axial length of the shaft 650 can be measured from the end652 to the second axial face 657. Yet another axial length of the shaft650 can be measured from the first axial face 655 to the second axialface 657.

As shown in FIG. 6, an axial gap (Δz) can exist between the end 664 ofthe bushing 660 and the second axial face 657 of the shaft 650. As anexample, the axial gap (Δz) may be an adjustable parameter. For example,the axial gap (Δz) may be set during assembly from a distance ofapproximately 0 to approximately 1 mm or less (e.g., consider a rangefrom approximately 0.01 mm to approximately 0.5 mm). As an example, theaxial gap (Δz) may be non-existent where the end 664 of the bushing 660contacts the second axial face 657 of the shaft 650. As an example, oneor more dimensions of the mesh spacer 670 may be selected to determinewhether the axial gap (Δz) exists and/or, for example, a size of theaxial gap (Δz). As an example, an axial gap (Δz) may exist depending ona manner in which the plug 690 seats in the wastegate seat 626. Forexample, where force is applied to the plug 690 of the wastegate 605, anaxial gap may be formed or not. In such an example, the plug 690 caninclude a surface profile such as a toroidal surface profile thatcontacts a surface profile of the wastegate seat 626 such as a conicalprofile.

In the example of FIG. 6, the surface 644 of the control arm 640 may bepositioned with respect to the end 662 of the bushing 660 (e.g., an endsurface of the bushing 660). In such an example, the surface 644 maycontact the end 662, for example, during formation of the weld 645. Insuch an example, the surface 644 and the end 662 may be at zeroclearance. Where the mesh spacer 670 is compressed axially from a freestanding state, the mesh spacer 670 can exert a force that biases theshaft 650 axially inwardly in a direction toward the interior space.Such a force may be referred to as a load where the shaft 650 is loadedwith respect to the bushing 660. At a time of assembly (e.g., formationof the weld 645), such a load may be referred to as a preload. Such anapproach may help to reduce an amount of dynamic axial movement of thecontrol arm 640 that may cause a clearance to form between the surface644 and the end 662, upon which reduction of the clearance and contactbetween the surface 644 and the end 662 may cause undesirable noise. Asan example, axial movement as associated with temperature (e.g., thermalexpansion) may occur. For example, where the shaft 650 expands axiallyresponsive to an increase in temperature (e.g., according to acoefficient of thermal expansion), the rate of expansion may berelatively less than a rate of movement (e.g., dynamic axial movement)that occurs responsive to a change in an operational condition (e.g.,exhaust pulse, controller action, vehicle vibration, etc.).

As an example, an amount of preload may help to maintain a clearance(e.g., the axial gap (Δz)), if desired, between the end 664 of thebushing 660 the second axial face 657 of the shaft 650. Such a preload,or load during operation, may help to reduce dynamic axial movement thatmay cause contact between the end 664 and the second axial face 657,which may generate undesirable noise. As an example, at a time ofassembly, a clearance may be referred to as a residual clearance (e.g.,a residual axial gap), which may be expected to be within a range oftolerances; noting that during operation, such a clearance may changeresponsive to one or more operational conditions. Such a clearance mayallow for proper seating of the plug 690 on the wastegate seat 626 suchthat the wastegate 605 operates optimally (e.g., with no, reduced orminimal leakage of exhaust, etc.). A residual clearance (e.g., aresidual axial gap), if and as desired, can correspond to a state of theplug 690 with respect to the wastegate seat 626 at a time of fixation ofthe control arm 640 to the shaft 650, which can correspond to an amountof preload imparted by the mesh spacer 670. For example, force may beapplied to the wastegate 605 such that the plug 690 seats properly withrespect to the wastegate seat 626 to achieve a desired static statewhere fixation of the control arm 640 to the shaft 650 occurs in thatdesired static state (e.g., with corresponding positions of componentsand mesh spacer preload).

The assembly 600 of FIG. 6 can utilize the mesh space 670 to properlyposition the wastegate 605, which may be a monoblock wastegate (e.g.,flapper valve), into the wastegate seat 626 through flexibility of themesh spacer 670 during the assembly process. As an example, the meshspace 670 can compensate part-to-part variation of dimensions and helpassure adequate sealing. During operational life-time of a turbocharger,the mesh space 670 can help to maintain a defined position (e.g., viaimparting a preload, load, etc.). The mesh spacer 670 can be a metalmesh spacer that is formed of deformable metal wire, deformable metalfoam, etc. (e.g., consider a metal and/or an alloy mesh). The meshspacer 670 can be made of a material that can withstand temperatures upto approximately 800 degrees C. Such a mesh spacer can be flexible up tosuch temperatures such that the mesh spacer can impart a biasing forcewithin an assembly. For example, the mesh spacer 670 can impart a load(e.g., force) or biasing force upon assembly (e.g., preload) and duringoperation (e.g., operational load). As an example, the mesh spacer 670can be an anti-sticking mechanism that acts to reduce sticking of thewastegate 605. For example, the flexibility of the mesh spacer 670 mayallow for relatively small amounts of movement as may occur in responseto rotation of the shaft 650 in the bore 612 of the housing 610, inresponse to temperature changes (e.g., noting different materials canexhibit different thermal coefficients of expansion, etc.), and/or inresponse to one or more other conditions. The mesh spacer 670 can helpto reduce undesirable vibration and, for example, noise. Such reductionsin undesirable behavior can enhance controllability and operationallife-time. As an example, the mesh spacer 670 can operate as a damperthat acts to damp various types of motion (e.g., to damp axial movementof the shaft 650 axially outwardly toward the exterior space, to dampaxial tilting movement of the shaft 650 in the bushing 660, etc.).

As an example, the mesh spacer 670 can operate as a hindrance to flow ofexhaust. In such an example, as the mesh spacer 670 compresses, itsporosity (e.g., free space) can decrease and make a more tortuouspath(es) as to flow of exhaust. Such an approach can help to reduceleakage of exhaust from an interior space of the turbine housing 610 toan exterior space (e.g., ambient space, environment, etc.). A reductionin leakage of exhaust can improve environmental performance.

As an example, the mesh spacer 670 can be positioned without fixation.For example, the mesh spacer 670 can be included in the assembly 600without welding of the mesh spacer 670 to one or more other components.In such an example, the mesh spacer 670 may be referred to as a floatingmesh spacer as it can move responsive to forces without being physicallyfixed to one or more other components. As an example, the mesh spacer670 may be serviceable. For example, where the mesh spacer 670 is afloating mesh spacer, it may be removed without having to unfix it fromone or more other components of the assembly 600, which may be requiredwhere a mesh spacer is welded or otherwise fixed to one or more othercomponents of an assembly.

As an example, the mesh spacer 670 can be made of a material such asstainless steel or INCONEL® alloy. As an example, during operation, theshaft 650 may rotation a number of degrees. For example, consider acontroller that is operatively coupled to the control arm 640 that canrotate the shaft 650 by approximately 60 degrees or less (e.g., considera maximum rotation of approximately 45 degrees). As an example, acontroller may cause the shaft 650 to rotate at a rotational rate indegrees per unit time (e.g., or radians per unit time). For example,consider a rotational rate of approximately 100 degrees per second orless (e.g., consider a rotational rate of approximately 50 degrees persecond). As an example, during operation of a turbocharger that includesthe assembly 600, the mesh spacer 670 may experience an amount ofdeformation. As to an axial deformation, consider an amount ofdeformation of the order of approximately 2 mm or less, of the order ofapproximately 1 mm, etc. For example, consider an assembly that includesan estimated mesh spacer deformation of approximately 0.5 mm axially. Asan example, an estimated mesh spacer deformation, which may be adesign/assembly parameter, may depend on whether an axial gap isutilized or not (see, e.g., the axial gap Δz). Where no axial gapexists, a mesh spacer may impart a load while not experiencing asubstantially amount of axial deformation. As an example, a mesh spacermay impart a load (e.g., a biasing force) that may act to stabilize ashaft axially (e.g., with respect to an axis of a stepped bore of abushing in which a portion of the shaft is disposed).

As an example, a mesh spacer may be selected based on stiffness. Forexample, an amount of wire, a diameter of wire, a winding form of wire,etc. may determine stiffness. Stiffness can define rigidity of a meshspacer as to the extent to which the mesh spacer resists deformation inresponse to an applied force. As an example, a spring constant may beutilized to characterize a mesh spacer.

FIG. 7 is a series of views of examples of mesh spacers 670, 701, 702and 703. The mesh spacer 670 may be made from compressing wire. As anexample, the mesh spacer 670 may be resilient to a predetermined extent(e.g., a resilient mesh spacer). For example, the mesh spacer 670 mayhave a first shape and absorb energy when loaded with force with acorresponding change in the first shape to a second shape and thenreturn to the first shape after unloading of the force. As an example,the mesh spacer 670 may be characterized in part by a compressibility,which may optionally be approximately zero or may be of a value akin toa spring constant where force can compress the mesh spacer 670 in itsaxial dimension, however, a limited amount that may be predetermined andthat may be non-linear with respect to force. For example, a mesh spacermay be defined in part by an uncompressed axial length in anuncompressed state and a compressed axial length in a compressed state.During operation of a turbocharger, a mesh spacer may be of an axiallength that is in a range between the uncompressed axial length and thecompressed axial length. As an example, the difference between these twolengths may be an axial distance that is, for example, less than 1 mm,for example, less than about 0.5 mm, for example, less than about 0.1 mmor, for example, less than about 0.05 mm. As an example, a mesh spacermay be characterized at least in part by a Poisson ratio that definestransverse strain to axial strain. For example, upon compression in anaxial direction, a mesh spacer may expand in a transverse direction.

As an example, a mesh spacer may be a resilient ring shaped mesh spacerthat includes a pre-determined uncompressed operational axial length anda predetermined compressed operational axial length where a differencebetween the axial lengths is less than a specified axial distance.

As an example, a mesh spacer may be constructed of compressed wire suchthat surface of a side of the mesh spacer is reduced (e.g., contactsurface) in comparison to a solid spacer. In such an example, frictionmay be reduced when compared to a solid spacer. As an example, where amesh spacer is resilient, the mesh spacer may act to absorb energy suchas axial thrust energy associated with axial movement of a shaft. Insuch an example, the mesh spacer may help to damp energy and reduce wearof one or more components of an assembly.

As an example, a mesh spacer can form a tortuous path for passage of gas(e.g., exhaust gas). For example, a mesh spacer may form one or moretortuous paths that can act to hinder passage of gas. In such anexample, where a mesh spacer is compressible, the paths may be alteredand, for example, hinder gas flow to a greater extent when compressed.As mentioned, a mesh spacer may be characterized at least in part by aPoisson's ratio (e.g., Poisson effect) where an amount of axialcompression or expansion corresponds to an amount of radial expansion orcompression, respectively. As an example, a mesh spacer may be made ofmetal, alloy, carbon fiber, ceramic, or a composite material. As anexample, a material of construction and/or a shape of a mesh spacer maydetermine a Poisson's ratio. For example, a mesh spacer may have aPoisson's ratio determined by the shape of the mesh spacer and, forexample, how the mesh spacer was constructed (e.g., amount of wire,compression force to form the mesh ring, etc.).

In the example of FIG. 7, the mesh spacer 670 can be a metallic ring(e.g., metal, alloy), a ceramic ring or a composite material ring. As anexample, a mesh spacer can be metallic and formed of a self-lubricatingsteel (e.g., low friction steel alloys). As an example, a bushing may beformed of a metal or an alloy. As an example, a bushing can be made of aself-lubricating steel. As an example, a part (e.g., a mesh spacer, abushing, etc.) may be cast and/or sintered. As an example, a turbinehousing may be made of metal or alloy. As an example, a turbine housingmay be a cast iron or a cast stainless steel. As an example, a wastegateseat may be machined, for example, to achieve a desired finish.

FIG. 7 shows various examples of dimensions 701 with respect to the meshspacer 670, which can include axial and radial dimensions. FIG. 7 showsvarious examples of sizes of a mesh spacer with respect to a shaftdimension such as the dimension d_(e) of the end portion 653 of theshaft 650.

FIG. 7 shows various examples of cross-sectional profiles of a meshspacer. As shown, a cross-sectional profile can include straight and/orcurved perimeter portions. As mentioned, shape of a mesh spacer caninfluence behavior of a mesh spacer (e.g., static behavior and/ordynamic behavior). As an example, shape and/or size of a mesh spacer maybe utilized as parameters that can determine behavior of a mesh spacer.For example, consider shaping a mesh spacer to achieve a desired forceversus axial length relationship. In such an example, a mesh spacer mayhave a smaller cross-sectional area near one or more of its axial facessuch that less material is compressed and, correspondingly, less changein force occurs; whereas, as further axial compression occurs, thecross-sectional area increases such that more material is compressedand, corresponding, a greater change in force occurs. In such anexample, the mesh spacer can become stiffer responsive to axialcompression in a desired manner. As another example, consider a meshspacer with a neck, which may be between two opposing axial endportions. In such an example, the neck may be of a lessercross-sectional area such that axial compression of the neck occursprior to any substantial amount of axial compression of the axial endportions. In such an example, upon compression of the neck, furthercompression may occur via one or both of the axial end portions, whichare of greater cross-sectional area. In FIG. 7, an example of a meshspacer with a neck and axial end portions is shown as the lowermost ofthe examples 703. Such a mesh spacer may provide a customized stiffnesscurve via one or more features (e.g., shape, shapes, size, sizes, etc.).

FIG. 8 is a cross-sectional view of the bushing 660 along with variousdimensions. As shown, the stepped bore 661 includes a bore surface 663disposed at a diameter Db_(i2) and a bore surface 665 disposed at adiameter D_(bi1). The axial face 667 may be an annular axial face thathas an inner dimension approximately that of the diameter of the boresurface 665 and that has an outer dimension approximately that of thediameter of the bore surface 663.

FIG. 9 is a series of views of an example of the mesh spacer 670 indifferent states 910, 920 and 930. As shown, the state 910 may beconsidered to be an uncompressed state, the state 920 may be consideredto be an assembled state where an amount of load is imparted and thestate 930 may be considered to be an operational state where anoperational force causes the mesh spacer 670 to compress (e.g., axially)compared to the state 920.

As shown in FIG. 9, the porosity of the mesh spacer 670 can change in astate dependent manner. For example, the porosity of the mesh spacer 670can decrease in moving from the state 910 to the state 920 to the state930. In such a progression (e.g., from the state 920 to the state 930),tortuosity of a path or paths of potential exhaust leakage can decrease.

In the state 920, a reaction force (F_(R)) is shown as being imparted tothe control arm 640, which is responsive to force (e.g., load F_(L))imparted by compression of the mesh spacer 670. As shown in FIG. 7, aPoisson ratio may be defined for the mesh spacer 670. Such deformationmay help to reduce leakage of exhaust and/or to help center the shaft650 with respect to the bushing 660.

FIGS. 10, 11, 12, 13 and 14 can be part of an example of a method thatcan assemble various components to form an assembly such as the assembly600 of FIG. 6. For example, a method can be performed according toassemblies 1000 of FIG. 10, 1100 of FIG. 11, 1200 of FIG. 12, 1300 ofFIG. 13 and 1400 of FIG. 14.

As shown in FIG. 10, the assembly 1000 includes the wastegate 605 andthe mesh spacer 670, which can be positioned on the wastegate 605.

As shown in FIG. 11, the assembly 1100 includes the turbine housing 610and the bushing 660, which can be inserted into the turbine housing 610.The bushing 660 can be secured to the turbine housing 610, for example,via one or more fixation mechanisms (e.g., welding, crimping, etc.).

As shown in FIG. 12, the assembly 1200 includes the housing 610, thewastegate 605, the bushing 660 and the mesh spacer 670. As shown, theassembly 1000 of FIG. 10 can be inserted into the bushing 660, which canbe secured to the turbine housing 610.

As shown in FIG. 13, the assembly 1300 includes the components of theassembly 1200 of FIG. 12 along with the control arm 640, which can bepositioned with respect to the wastegate 605.

As shown in FIG. 14, the assembly 1400 includes the components of theassembly 1300 of FIG. 13 where one or more forces can be applied via oneor more tools. For example, a tool may be utilized to force the plug 690of the wastegate 605 against the wastegate seat 626 of the turbinehousing 610 to assure proper seating and sealing. In such an approach,the control arm 640 can be fixed to the end portion 653 of the shaft 650of the wastegate 605. As mentioned with respect to the example of FIG.6, fixation can occur in a manner where the mesh spacer 670 imparts apreload.

As an example, the mesh spacer 670 may apply a load that is sufficientto diminish axial movement of the wastegate 605 under the influence ofgravity. For example, the mesh spacer 670 may be of a sufficientstiffness (e.g., and compression) such that no substantial change occursof the wastegate 605 when a rotational axis of the shaft 650 issubstantially aligned with gravity. For example, where the assembly 1400is installed in a vehicle and where the vehicle changes its orientation(e.g., on a hill, etc.), the wastegate 605 may remain axially positionedas desired without a substantial change in its axial position due togravity. Without such a mesh spacer, the wastegate 605 may slide axiallywhere one or more axial clearances exist.

As an example, the control arm 640 can be positioned, such that uponfixation to the end portion 653 of the shaft 650, contact (e.g., zeroclearance) is targeted between the control arm 640 and the bushing 660.As an example, a clearance may be desired rather than contact (e.g.,consider a clearance less than approximately 1 mm). As an example, afixation process (e.g., welding, etc.) may contact a control arm and abushing in a manner that causes a mesh spacer to be deformed followed byfixing the control arm to a shaft of a wastegate where the shaft isreceived at least in part in a stepped bore of the bushing. In such anexample, the control arm/shaft can be spatially fixed with a plug of thewastegate in a centered position with respect to a wastegate seat of ahousing where the wastegate may be a monoblock wastegate that includesthe shaft as an integral portion thereof. Such a process may include,for example, welding in situ of the control arm to the shaft of thewastegate.

As an example, a turbocharger turbine wastegate assembly can include aturbine housing that includes an exterior surface, an interior surfacethat includes a wastegate seat, and a bore that extends between theexterior surface and the interior surface; a bushing disposed at leastpartially in the bore of the turbine housing where the bushing includesa stepped bore that includes an axial face; a wastegate that includes ashaft, a plug and an arm, where the arm extends from the shaft and theplug extends from the arm, where the shaft includes an end portion, afirst axial face, a journal portion, a second axial face and a shoulderportion, where the first axial face is defined at least in part by anend portion diameter and a journal portion diameter, and where thesecond axial face is defined at least in part by the journal portiondiameter and a shoulder portion diameter; a mesh spacer disposedradially about an axial length of the end portion of the shaft betweenthe axial face of the stepped bore of the bushing and the first axialface of the shaft; and a control arm connected to the end portion of theshaft where an axial length of the bushing is disposed between the meshspacer and the control arm. In such an example, a weld can be includedthat connects the control arm to the end portion of the shaft.

As an example, a mesh spacer can impart a load between an axial face ofa stepped bore of a bushing and a first axial face of a shaft of awastegate. In such an example, the load may be a preload at a time ofassembly.

As an example, an axial gap can exists between an end of a bushing and asecond axial face of a shaft of a wastegate. In such an example, theaxial gap can be in an interior space where exhaust may flow (e.g., achamber space of a wastegate/wastegate seat).

As an example, an axial length of a bushing can exceed an axial lengthof a bore of a turbine housing such that one or more ends of the bushingextend axially outwardly from one or more corresponding end openings ofthe bore.

As an example, a bushing can be axially located with respect to aturbine housing. In such an example, the bushing can be axially locatedsuch that the bushing remains axially fixed at a fixation location;noting that some amount of thermal expansion may occur as to the bushingwith respect to the turbine housing.

As an example, a stepped bore of a bushing can include a first boreportion and a second bore portion. In such an example, a diameter of thesecond bore portion can exceed a diameter of the first bore portion. Insuch an example, an axial length of the second bore portion can exceedan axial length of the first bore portion. As an example, a mesh spacercan be disposed in a second bore portion of a bushing that includes astepped bore (e.g., as defined by a first bore portion and a second boreportion). As an example, a transverse dimension of a mesh spacer mayexceed a diameter of a first bore portion of a stepped bore of abushing.

As an example, a mesh spacer may contact an end portion of a shaft of awastegate where the shaft is received at least in part in a stepped boreof a bushing that is received at least in part in a bore of a housing.

As an example, a mesh spacer may be a floating mesh spacer. For example,a mesh spacer may be positioned in an assembly without being physicallyconnected to another component via a fixation mechanism such as welding.In such an example, the mesh spacer may float in that it may moveindependently from one or more other components while responding tomovement of one or more other components.

As an example, a mesh spacer can include an uncompressed, free-standingstate and a compressed, installed state.

As an example, a wastegate may be a unitary component. For example, awastegate can be a monoblock wastegate in that it is formed from asingle piece of material.

As an example, a method can include positioning a mesh spacer on an endportion of a shaft of a wastegate to form a first subassembly; providinga second subassembly that includes a bushing in a bore of a turbinehousing where the bushing includes a stepped bore that includes an axialface; inserting at least a portion of the first subassembly into thestepped bore to contact the mesh spacer and the axial face; and fixing acontrol arm to the end portion of the shaft where the mesh spacerimparts a load to the bushing and the wastegate.

Although some examples of methods, devices, systems, arrangements, etc.,have been illustrated in the accompanying Drawings and described in theforegoing Detailed Description, it will be understood that the exampleembodiments disclosed are not limiting, but are capable of numerousrearrangements, modifications and substitutions.

What is claimed is:
 1. A turbocharger turbine wastegate assemblycomprising: a turbine housing that comprises an exterior surface, aninterior surface that comprises a wastegate seat, and a bore thatextends between the exterior surface and the interior surface; a bushingdisposed at least partially in the bore of the turbine housing whereinthe bushing comprises a stepped bore that comprises an axial face; awastegate that comprises a shaft, a plug and an arm, wherein the armextends from the shaft and the plug extends from the arm, wherein theshaft comprises an end portion, a first axial face, a journal portion, asecond axial face and a shoulder portion, wherein the first axial faceis defined at least in part by an end portion diameter and a journalportion diameter, and wherein the second axial face is defined at leastin part by the journal portion diameter and a shoulder portion diameter;a mesh spacer disposed radially about an axial length of the end portionof the shaft between the axial face of the stepped bore of the bushingand the first axial face of the shaft; and a control arm connected tothe end portion of the shaft wherein an axial length of the bushing isdisposed between the mesh spacer and the control arm.
 2. Theturbocharger turbine wastegate assembly of claim 1 comprising a weldthat connects the control arm to the end portion of the shaft.
 3. Theturbocharger turbine wastegate assembly of claim 1 wherein the meshspacer imparts a load between the axial face of the stepped bore of thebushing and the first axial face of the shaft.
 4. The turbochargerturbine wastegate assembly of claim 1 wherein an axial gap existsbetween an end of the bushing and the second axial face of the shaft. 5.The turbocharger turbine wastegate assembly of claim 1 wherein an axiallength of the bushing exceeds an axial length of the bore of the turbinehousing.
 6. The turbocharger turbine wastegate assembly of claim 1wherein the bushing is axially located with respect to the turbinehousing.
 7. The turbocharger turbine wastegate assembly of claim 1wherein the stepped bore of the bushing comprises a first bore portionand a second bore portion.
 8. The turbocharger turbine wastegateassembly of claim 7 wherein a diameter of the second bore portionexceeds a diameter of the first bore portion.
 9. The turbochargerturbine wastegate assembly of claim 8 wherein an axial length of thesecond bore portion exceeds an axial length of the first bore portion.10. The turbocharger turbine wastegate assembly of claim 7 wherein themesh spacer is disposed in the second bore portion.
 11. The turbochargerturbine wastegate assembly of claim 7 wherein a transverse dimension ofthe mesh spacer exceeds a diameter of the first bore portion.
 12. Theturbocharger turbine wastegate assembly of claim 1 wherein the meshspacer contacts the end portion of the shaft.
 13. The turbochargerturbine wastegate assembly of claim 1 wherein the mesh spacer is afloating mesh spacer.
 14. The turbocharger turbine wastegate assembly ofclaim 1 wherein the mesh spacer comprises an uncompressed, free-standingstate and a compressed, installed state.
 15. The turbocharger turbinewastegate assembly of claim 1 wherein the wastegate comprises a unitarycomponent.
 16. A method comprising: positioning a mesh spacer on an endportion of a shaft of a wastegate to form a first subassembly; providinga second subassembly that comprises a bushing in a bore of a turbinehousing wherein the bushing comprises a stepped bore that comprises anaxial face; inserting at least a portion of the first subassembly intothe stepped bore to contact the mesh spacer and the axial face; andfixing a control arm to the end portion of the shaft wherein the meshspacer imparts a load to the bushing and the wastegate.